Method, apparatus, and system for deinterleaving data

ABSTRACT

A method, apparatus, and system for deinterleaving data.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication 62/717,770filed Aug. 10, 2018, titled “Interleaver,” whichis incorporated by reference in its entirety for all purposes. Thisapplication is related to U.S. patent application Ser. No. 15/637,808,filed Jun. 29, 2017, titled “FORWARD ERROR CORRECTION SYSTEMS ANDMETHODS,” which is incorporated by reference in its entirety for allpurposes. This application is related to U.S. patent application Ser.No. 16/102,400, filed Aug. 13, 2018, titled “INTERLEAVER,” which isincorporated by reference in its entirety for all purposes.

BACKGROUND

A deinterleaver is often used in certain types of communication systems

BRIEF DESCRIPTION OF THE FIGURES

Various aspects and embodiments of the application will be describedwith reference to the following example embodiments. It should beappreciated that the figures are not necessarily drawn to scale.

FIG. 1a is a simplified illustration of an optical communication system,in accordance with an embodiment of the present disclosure;

FIG. 1b is a simplified method for transmitting information in acommunication system, in accordance with an embodiment of the presentdisclosure;

FIG. 1c is a simplified method for receiving information in acommunication system, in accordance with an embodiment of the presentdisclosure;

FIG. 2 is a simplified illustration of spreading out an error burst, inaccordance with an embodiment of the present disclosure;

FIG. 3 is a simplified illustration of a table showing a mean, minimum,and maximum of occurrences of a bits in each reliability class in aconstituent code for modulations of interest, in accordance with anembodiment of the present disclosure;

FIG. 4 is a simplified illustration of a table showing a bit index in anoutput group for encoded bits in a block for 16 QAM, in accordance withan embodiment of the present disclosure;

FIG. 5 is a simplified illustration of a table showing a bit index in anoutput group for encoded bits in a block for QPSK, in accordance with anembodiment of the present disclosure;

FIG. 6 is a simplified illustration of portioning a buffer into 4subsets, in accordance with an embodiment of the present disclosure;

FIG. 7 is a simplified illustration of a mapping showing a writesequence for a buffer, in accordance with an embodiment of the presentdisclosure;

FIG. 8 is an illustration of a table for unmapping intra-blockinterleaving, in accordance with an embodiment of the presentdisclosure;

FIG. 9 is a simplified illustration of decoders reading from a buffer,in accordance with an embodiment of the present disclosure;

FIG. 10 is a simplified method for deinterleaving, in accordance with anembodiment of the present disclosure; and

FIG. 11 is a simplified illustration of a deinterleaving system, inaccordance with an embodiment of the present disclosure.

SUMMARY

A method, apparatus, and system for a deinterleaver.

DETAILED DESCRIPTION

In some embodiments, a communication system may transmit data from atransmitter to a receiver over a communication link. In manyembodiments, a communication link may be exposed to environmentalconditions that may interfere with data transmitted over a communicationlink. In certain embodiments, a way to correct for interference over acommunication link may be to use an encoder on a transmission side of acommunication link. In most embodiments, a way to correct forinterference over a communication link may be to use a decoder on areceiver side of a transmission link. In some embodiments, an errorcorrection code used by an encoder and decoder may be composed ofsmaller “constituent codes.” In most embodiments, an error correctioncode may add redundant bits to specific information bits that may allowrecovery of some or all the information when one or more of theinformation bits has become corrupted. In different embodiments, theamount of corrupted information that may be recovered may depend on theamount of additional or redundant bits added to information bits. Incertain embodiments, a code word may be an element of a particular code.In a particular embodiment, for example, a size 1024×1024 Product Codemay be a square array of bits where each row and each column form aconstituent code of size 1024. In many embodiments, a way to correct forinterference over a communication link may be to use an interleaver on atransmitter side of a transmission link. In many embodiments, a way tocorrect for interference over a communication link may be to use adeinterleaver on a receiver side of a transmission link.

In many embodiments, an encoder may encode data to be transmitted over acommunication link. In most embodiments, a decoder may decode data thathas been received over a transmission link. In certain embodiments, aninterleaver may change the order of data to be transmitted over a link.In many embodiments, a deinterleaver may reverse a change of order ofdata received over a link.

Often, a transmitter may use a modulation scheme for data to betransmitted using a signal to a receiver. Conventional modulationschemes associate data bits with symbols. Quadrature amplitudemodulation (QAM) is one example type of a typical type of modulationscheme and is commonly used in many communication systems includingfiber optical and digital radio communications. Generally, the number ofdifferent symbols in a modulation format determines the order of adigital communication scheme. Conventionally, higher order modulationformats enable carrying more bits of information or parity bits persymbol. Usually, by selecting a higher order format of QAM, the datarate of a link can be increased.

Conventionally, a QAM scheme may be associated with a constellationdiagram having M points arranged in a two-dimensional plane. Usually,the M points represent the M possible symbols to which data bits may bemapped, where M is an integer. For example, an 8QAM scheme may beassociated with a constellation diagram having 8 points arranged in atwo-dimensional plane representing 8 possible symbols to which data bitsmay be mapped. As another example, in conventional 16QAM, data bits aremapped to 16 different symbols. Generally, each particular one of the Mpoints may be associated with a label indicating the bit sequence mappedto the symbol represented by the particular one point. For example, aparticular one of the 8 points in a constellation diagram for 8 QAM maybe associated with a label (e.g., “010”) indicating that data bits “010”are mapped to the symbol represented by the particular one point.Typically, in the presence of noise those 3 bits may exhibit differenterror probabilities, so they are in different reliability classes.Conventional examples of QAM schemes include 8QAM, 16QAM, 32QAM, 64QAM,and 256QAM schemes. Other conventional modulation schemes include BPSKand QPSK.

Typically, in communication systems, data transmitted over a link may besubjected to an environmental condition that may cause interference fora period of time and then cease to cause interference. Generally, theinterference for a period of time may cause the data within that periodof time to be corrupted so that the data may not be recovered usingerror checking information encoded in the data. Usually, if data isreordered, such that errors due to interference is spread out over agreater period of time, then the errors may be corrected. In aparticular example, if an error occurring for 1 second over 10 secondsof transmitted data was changed to instead occur across the 10 secondsof data, then the amount of error per second of data transmitted can bereduced by a factor of 10. In most embodiments, use of an interleaverand deinterleaver may enable errors to be distributed across more datainstead of being concentrated in the portion of time where the erroroccurred.

In certain embodiments, deinterleaving may be a process of restoring anorder of transmission of bits from an demodulator when receiving thebits on the Horizontal and Vertical polarizations of optical channels,where the Horizontal and Vertical polarization may exhibit differentsignal to noise ratios and error rates, so bits transmitted over themare also in different reliability classes. In many embodiments, adeinterleaver may help insure bursts of errors do not cause decodingfailures. In some embodiments, a deinterleaver may restore bits from Hand V symbols appear that previously appeared equally in constituentcodes. In certain embodiments, a deinterleaver may reverse the changesmade by an interleaver to insure that bits in each reliability class (inhigher order modulations) are balanced in constituent codes. In manyembodiments, a deinterleaver may reverse changes made by an interleaverto insure that bits with correlated errors (in non-Gray mappedconstellations) appear in different constituent codes.

In many embodiments, a deinterleaver buffer may refer to a set ofmetrics that the deinterleaver deinterleaves or changes the order of ina given period of time. In certain embodiments, a bit metric may be arepresentation of a demodulator decision about a bit being correct andprobability of the reliability of that decision. In most embodiments, abit metric may be referred to interchangeable herein as a metric. Inmany embodiments, a bit metric may be transformed into a bit by one ormore of the techniques described herein. In certain embodiments, andeinterleaver may change a bit metric into a bit. In other embodiments,a decoder may change a bit metric into a bit. In some embodiments, whichmay be referred to herein as hard decoding, a metric itself may consistof a single bit, indicating if the received bit was a 0 or 1. In otherembodiments, a metric may consist of several bits. In a particularembodiment, a deinterleaver buffer size may be 172,032 metrics. In someembodiments, 172,032 metrics may be organized as an (84, 8) array of16×16 metric blocks. In certain embodiments, an intra-blockdeinterleaver may reorder metrics in 16×16 blocks to undo changes by aninterleaver that insured that the bits in each row and column of a blockof an encoder output are remapped almost uniformly in a block fortransmission on the line. In many embodiments, an inter-blockdeinterleaver may reverse changes in order by an interleaver that causednearby symbols on a line to contain bits that are widely separated in anencoder output.

In certain embodiments, an inverse of an intra-block permutation appliedby a deinterleaver may be applied to blocks in a buffer before theblocks are read by one or more decoders. In some embodiments, a buffermay be partitioned in an upper half of 42 rows and a bottom part of 42block rows. In many embodiments, a buffer may be partitioned into 4subsets, each containing 21×8 blocks or 336×128 bits. In certainembodiments, a first subset may contain row blocks 0, 2, . . . , 40. Inthose certain embodiments, a second subset may contain row blocks 1, 3,. . . , 41. In those certain embodiments, a third subset may contain rowblocks 42, 44, . . . , 82. In those certain embodiments, a fourth subsetmay contain row blocks 43, 45, . . . , 83.

In certain embodiments, on output, groups of 8 metrics may be written inturn to each subset, writing them in a column of bits before proceedingto the next columns of bits. In some embodiments, a first 8 metrics maybe written from the top of a first column (i.e. column 0) of a firstsubset, then a first 8 metrics from a first column of a second, third,and forth subset. In many embodiments, the first 8 metrics from foursubsets may be followed by writing a next 8 metrics in the first columnof a first, second, third, and fourth subsets. In many embodiments,after 42 cycles of writing 4×8 bits each, a first bit column of aninterleaver buffer may be completely written in, and an output processmay continue by writing bit columns 1 to 127. In most embodiments,writing by columns of bits may be superior to writing by rows. In someembodiments, interleaver columns may be much longer than rows, and thusbits in a column may be spread over more constituent codes than bits ina row. In certain embodiments, writing columns when columns are longerthan rows may increase a tolerance to long bursts or errors. Thus, inmost embodiments, a deinterleaver may perform the inverse of what aninterleaver did to create a buffer on a transmit side.

In some embodiments, intra-block deinterleaving may be specified by atable, which may indicate for each metric in the block received to whata row and column the corresponding source bit belonged before beingintra-block interleaved, and thus to what row and column the metricshould be deinterleaved. In a particular embodiment, for example, atable may specify that the bit corresponding to metric (14, 15) of andeinterleaver input block (i.e. output in a buffer as written by ademodulator before such output is read by one or more decoders) wasplaced by an interleaver in row 1 (base 0) of column 0 and thecorresponding metric should be deinterleaved to (14,15).

In some embodiments, a deinterleaver may assume that symbol bits in eachreliability class in each constituent code word have been balanced. Incertain embodiments, each row and each column may have been mappeduniformly on all possible positions by an interleaver. In someembodiments, an even mapping may imply that each constituent codeword ismapped uniformly to H and V symbols, and that for 16 QAM bits in eachconstituent codeword are mapped uniformly to reliability classes ofsymbol bits. In most embodiments, a symbol bit may refer to the bitlabel or bits associated with a particular point or symbol in aconstellation.

In certain embodiments, there may be a mean, minimum and maximum numbersof occurrences of a bits in each reliability class in a constituent codefor modulations of interest. In some embodiments, an ideal balance maybe when a minimum and maximum are equal to a mean. In certainembodiments, a constituent codeword may have 256 bits. In someembodiments, for QPSK, the mean, max, and min may be 64. In manyembodiments, for 8QAM, the mean may be 42.66, the min may be 37, and themax may be 46. In other embodiments, for 16-QAM, the mean, max, and minmay be 32.

In some embodiments, deviations from the mean may be close to a standarddeviation produced by a random interleaver. In particular embodiments, aworst case may not be far from a mean and no significant differences indecoder performance may be observed compared to a random interleavers.In certain embodiments, spatial coupling between intersectingconstituent codes may contribute to the averaging process duringiterative decoding.

In some embodiments, a full rate deinterleaver may feed two half datarate decoders, 0 and 1. In some embodiments, successive rows of evenrows blocks may be read from a buffer and written to a first decoder 0.In many embodiments, successive odd block rows of blocks may be readfrom a buffer and used to feed a second decoder. In certain embodiments,a content of a deinterleaver buffer may read out row by rowdeinterleaving vertical segments of the buffer with alternative rowsfeeding different encoders, for example Product Code decoders. In someembodiments, a matrix of a decoder fed by a deinterleaver may beconsidered infinite as the data being deinterleaved by the deinterleavermay not have a defined end point as data may continue to bedemodulatored by a demodulator.

Refer now to the example embodiment of FIG. 1a . FIG. 1a is a simplifiedexample embodiment of an optical system with a link and twotransceivers, each transceiver with an encoder, decoder, mappermodulator, decoder, demapper, and demodulator. In FIG. 1a , opticaltransceiver 115 has encoder 120, interleaver 130 and mapper/modulator135. As well, transceiver 115 has demapper/demodulator 178,deinterleaver 180, and decoder 181. In the example embodiment of FIG. 1a, each functionality is shown as a separate box, however in alternativeembodiments functionality may be combined or shared depending on design.

Referring back to the example embodiment of FIG. 1a , encoder 120receives input signal 110 (step 180). Encoder 120 encodes input signal110 to generate a plurality of bits 126 (step 182). Interleaver 130interleaves the bits (step 183). Mapper/Modulator 135 modulates light tosend the plurality of signals across link 140 to transceiver 145 (step186).

Transceiver 145 has demapper/demodulator 155, interleaver 157, anddecoder 260. Demapper/demodulator 155 receives the symbols from opticallink 140 (step 190). Demapper/demodulator 155 associates the receivedsymbols with a plurality of bits (step 192) and assign to each bit ametric that indicates the probability that the transmitted bit was a 0or a 1. Refer back to the example embodiment of FIG. 1a ,demapper/demodulator 155 provides the plurality of metrics todeinterleaver 157 (step 193). Deinterleaver 157 deinterleaves the data(step 194). Decoder 160 decodes the metrics (step 196). Transceiver 145also has encoder 170, interleaver 172 and mapper/modulator 174. Encoder170, interleaver 172, and mapper modulator 175 act in a similar mannerto encoder 120, interleaver 130, and mapper/modulator 135 at Transceiver115. Similarly, decoder 181, deinterleaver 180 and demodulator/demapper178 of Transceiver 115 function similarly to demapper/demodulatore 155,interleaver 157, and decoder 160 of transceiver 145.

In the illustrative embodiment of FIG. 1a , modulator 135 is able totransmit the plurality of symbols optical link 240 by modulating theplurality of symbols onto a carrier light wave with 2 polarizations,which propagates over optical communications link 140. In theillustrative embodiment of FIG. 1a , mapper/modulator 135 may be enabledto associate the plurality of bits 110 with symbols 124 according to aQAM format.

In certain embodiments, an encoder such as encoder 120 of FIG. 1a , maygenerate a plurality of bits from an input signal using a turbo productcode (TPC). In some embodiments, an encoder such as encoder 120 of FIG.1a , may generate a plurality of bits from an input signal using aconvolutional low-density parity check code (LDPC). In furtherembodiments, an encoder such as encoder 120 of FIG. 1a , may generate aplurality of bits from an input signal using any suitable forward errorcorrection code. In many embodiments, a plurality of bits may includeparity bits generated by an encoder. In certain embodiments, an encodermay be implemented in hardware as circuitry. In some embodiments, anencoder may be implemented as part of an application-specific integratedcircuit (ASIC).

Refer now to the example embodiment of FIG. 2, which illustrates a bursterror with interleaved data. Data transmission 210 represents has beenexposed to burst error 230. In FIG. 2, data mapping 220 represents thedeinterleaved data of data transmission 210. In FIG. 2, bust error 230has, through a deinterleaving process, been spread out to be errors 240,245, 250, and 255. In most embodiments, spreading out a burst erroracross more data may enable better error recovery from the burst error.

Refer now to the example embodiment of FIG. 3, which shows a table amean, minimum, and maximum of occurrences of a bits in each reliabilityclass in a constituent code for sample modulations. In the table of FIG.3, for QPSK, the mean, max, and min are 64. In the table of FIG. 3, for8QAM, the mean is 42.66, the min is 37, and the max is 46. In the tableof FIG. 3, for 16-QAM, the mean, max, and min are 32.

Refer now to the example embodiment of FIG. 4, which illustratesbalancing symbol bits in each reliability class in each constituentcodeword for 16 QAM. The table of FIG. 4 shows to which bit in a groupof 8, each coded bit (before intra-block permutation) is mapped. Eachrow and each column is mapped uniformly on all possible positions. Inthis embodiment, this means that each constituent codeword is mappeduniformly to H and V symbols, and that for 16 QAM the bits in eachconstituent codeword are mapped uniformly to all reliability classes ofsymbol bits.

Refer now to the example embodiment of FIG. 5, which illustratesbalancing symbol bits in each reliability class in each constituentcodeword for QPSK. In this example embodiment, such a table is possibleas the indices of transmission of the bits on the line, taken modulo,where N is twice the number of bits per symbol S, are the same in eachblock. The table of FIG. 5 shows to which of the 4 reliability classes,each coded bit (before intra-block permutation) is mapped. In thisembodiment, each row and each column is mapped uniformly.

In most embodiments, such as for example in FIGS. 5 and 6, a table forbalancing symbol bits in each reliability class in each constituentcodeword may be possible when the indices of transmission of the bits onthe line, taken modulo N, where N is twice the number of bits persymbol, are the same in each block.

Refer now to the example embodiment of FIG. 6, which illustratespartitioning a buffer of a deinterleaver. In the example embodiment ofFIG. 6, a buffer is divided into a top portion of 42 rows and a bottomportion of 42 rows. The top portion is represented as 2 subsets 0 and 1.The lower portion is represented as two subsets 2 and 3. Overall, inthis embodiment, the buffer is divided into 4 parts, 0, 1, 2, and 3, byrow blocks. For example, the first partition contains rows blocks 0, 2,. . . , 40 and the second partition contains row blocks 1, 3, . . . ,41. The third partition contains row blocks 42, 44, . . . , 82 and thefourth partition contains row blocks 43, 45, . . . 83. Each of the foursubsets contains 21 by 8 blocks or 336 by 128 bits.

Refer now to the example embodiment of FIG. 7, which illustrates writingrows into a buffer from data received from a demodulator. In the exampleembodiment of FIG. 7, groups of 8 bits are written in turn from eachsubset, writing them into a column of bits before proceeding to the nextcolumns of bits. For example, as shown in FIG. 1, the first 8 bits arewritten to the top of first column of subset 0, then the first 8 bitsfrom the first column of subsets 1, 2 and 3. Those 32 bits are thenfollowed by the taking the next 8 bits in the first column of each ofthe subsets 0, 1, 2 and 3. After 42 such cycles of 4×8 bits each, thefirst bit column of the deinterleaver buffer will be completely written,and the output process continues by reading bit columns 1 to 127.

Refer now to the example embodiment of FIG. 8, which illustrates amapping table for intra-block deinterleaving. The example embodiment ofFIG. 8 is 16 by 16 table 300, that indicates the row and column of eachdestination bit for each source bit in the block. In FIG. 8, entry(14,15) 310 in row 1 (base 0) of column 0 indicates that the metric inrow 1 of column 0 should be placed in row 14 column 15 of the blockwritten to the decoder. In most embodiments, intra-block interleavingmay be performed on a deinterleaver buffer that is mapped into arrays of16 by 16 bits. In certain embodiments herein, the mapping of FIG. 8 maybe applied to each block in a buffer filled in by an demodulator.

Refer now to the example embodiment of FIG. 9, that illustrates two halfdecoders. In the example embodiment of FIG. 9 decoders 0 910 and encoder1 920 read from buffer 930. Decoder 0 910 and decoders 1 920 alternatereading lines in from buffer 930. In this example embodiment, decoders 0910 reads alternative lines in buffer 930 such as buffer line 1 940,buffer line 3 950, buffer line 5 960, buffer line 7 970 and buffer line9 980. In this example embodiment, encoder 1 930 feeds alternative linesin buffer 930 such as buffer line 2 945, buffer line 4 955, buffer line6 965, buffer line 8 976 and buffer line 10 985. Each row block containseight 16×16 blocks.

Refer now to the example embodiments of FIGS. 10 and 11, whichillustrate a sample interleaving process. Data is received fromdemodulator 1110 (step 1000). Data is written from according to writesequence 1110 in buffer 1120 (step 1005). Intra block demapping fromtable 1130 is applied to the data (step 1010) and the data is sent inalternating rows to decoder 0 1140 and decoder 1 1150 (Step 1015).

In a particular embodiments, for step 1005, a first 8 bits metrics iswritten from the top of a first column (i.e. column 0) of a firstsubset, then a first 8 bits metrics from the top of a first column of asecond, third, and forth subset. In these particular embodiments, thefirst 8 bits metrics from four subsets is followed by taking writing anext 8 bits metrics in the first column of a first, second, third, andfourth subsets. In these particular embodiments, after 42 cycles ofwriting 4×8 bits metrics each, a first bit metric column of adeinterleaver buffer are be completely written out in, and an outputprocess may continue by writing bit metric columns 1 to 127.

In some particular embodiments, for step 1010, “intra-blockdeinterleaving is specified by a table, such as the table of” FIG. 8,which indicates for each metric in the block received to what a row andcolumn the corresponding source bit belonged before being intra-blockinterleaved, and thus to what row and column the metric isdeinterleaved. In these some particular embodiments, as specified FIG.8, for example, the bit corresponding to metric (14, 15) of andeinterleaver input block (i.e. output in a buffer as written by ademodulator before such output is read by one or more decoders) waswritten in row 1 (base 0) of column 0 and the corresponding metricshould be deinterleaved to (14,15).

In some embodiments, one or more of the embodiments described herein maybe stored on a computer readable medium. In certain embodiments, acomputer readable medium may be one or more memories, one or more harddrives, one or more flash drives, one or more compact disk drives, orany other type of computer readable medium. In certain embodiments, oneor more of the embodiments described herein may be embodied in acomputer program product that may enable a processor to execute theembodiments. In many embodiments, one or more of the embodimentsdescribed herein may be executed on at least a portion of a processor.

In most embodiments, a processor may be a physical or virtual processor.In other embodiments, a virtual processor may be spread across one ormore portions of one or more physical processors. In certainembodiments, one or more of the embodiments described herein may beembodied in hardware such as a Digital Signal Processor DSP. In certainembodiments, one or more of the embodiments herein may be executed on aDSP. One or more of the embodiments herein may be programmed into a DSP.In some embodiments, a DSP may have one or more processors and one ormore memories. In certain embodiments, a DSP may have one or morecomputer readable storages. In many embodiments, a DSP may be a customdesigned ASIC chip. In other embodiments, one or more of the embodimentsstored on a computer readable medium may be loaded into a processor andexecuted.

Having thus described several aspects and embodiments of the technologyof this application, it is to be appreciated that various alterations,modifications, and improvements will readily occur to those of ordinaryskill in the art. Such alterations, modifications, and improvements areintended to be within the spirit and scope of the technology describedin the application. It is, therefore, to be understood that theforegoing embodiments are presented by way of example only and that,within the scope of the appended claims and equivalents thereto,inventive embodiments may be practiced otherwise than as specificallydescribed. In addition, any combination of two or more features,systems, articles, materials, and/or methods described herein, if suchfeatures, systems, articles, materials, and/or methods are not mutuallyinconsistent, is included within the scope of the present disclosure.

Also, as described, some aspects may be embodied as one or more methods.The acts performed as part of the method may be ordered in any suitableway. Accordingly, embodiments may be constructed in which acts areperformed in an order different than illustrated, which may includeperforming some acts simultaneously, even though shown as sequentialacts in illustrative embodiments.

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified.

The terms “approximately” and “about” may be used to mean within ±20% ofa target value in some embodiments, within ±10% of a target value insome embodiments, within ±5% of a target value in some embodiments, andyet within ±2% of a target value in some embodiments. The terms“approximately” and “about” may include the target value.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. The transitional phrases “consisting of” and “consisting essentiallyof” shall be closed or semi-closed transitional phrases, respectively.

The terms “approximately” and “about” may be used to mean within ±20% ofa target value in some embodiments, within ±10% of a target value insome embodiments, within ±5% of a target value in some embodiments, orwithin ±2% of a target value in some embodiments. The terms“approximately” and “about” may include the target value.

What is claimed is:
 1. A method for deinterleaving data comprising:writing data into a buffer having 172,032 metrics arranged into an 84 by8 array of 16 by 16 blocks; wherein the buffer is partitioned into 4subsets of rows according to a predetermined write sequence; applying amapping table to change data in each of the 16 by 16 block of arraysaccording to a table; wherein the table specifies a mapping of thelocation for each metric in the 16 by 16 block; and reading the data outof the buffer to serve as input for a first decoder and a seconddecoder.
 2. The method of claim 1 where the first elements of the 16 by16 table entries form a Latin square.
 3. The method of claim 1 whereinthe method is for deinterleaving data encoded using a 16 QAM modulation.4. The method of claim 3 wherein symbol bits in each reliability classare balanced in each constituent codeword.
 5. The method of claim 4wherein the indices of transmission of the metrics on the line, takenmodulo N, where N is twice the number of metrics per symbol, are thesame in each block.
 6. The method of claim 1 wherein the table is: 0,01,1 2,2 3,3 4,4 5,5 6,6 7,7 8,8 9,9 10,10 11,11 12,12 13,13 14,14 15,1514,15 15,0  0,1 1,2 2,3 3,4 4,5 5,6 6,7 7,8 8,9  9,10 10,11 11,12 12,1313,14 12,14 13,15 14,0  15,1  0,2 1,3 2,4 3,5 4,6 5,7 6,8 7,9  8,10 9,11 10,12 11,13 10,13 11,14 12,15 13,0  14,1  15,2  0,3 1,4 2,5 3,64,7 5,8 6,9  7,10  8,11  9,12  8,12  9,13 10,14 11,15 12,0  13,1  14,2 15,3  0,4 1,5 2,6 3,7 4,8 5,9  6,10  7,11  6,11  7,12  8,13  9,14 10,1511,0  12,1  13,2  14,3  15,4  0,5 1,6 2,7 3,8 4,9  5,10  4,10  5,11 6,12  7,13  8,14  9,15 10,0  11,1  12,2  13,3  14,4  15,5  0,6 1,7 2,83,9 2,9  3,10  4,11  5,12  6,13  7,14  8,15 9,0 10,1  11,2  12,3  13,4 14,5  15,6  0,7 1,8 15,7  0,8 1,9  2,10  3,11  4,12  5,13  6,14  7,158,0 9,1 10,2  11,3  12,4  13,5  14,6  13,6  14,7  15,8  0,9  1,10  2,11 3,12  4,13  5,14  6,15 7,0 8,1 9,2 10,3  11,4  12,5  11,5  12,6  13,7 14,8  15,9   0,10  1,11  2,12  3,13  4,14  5,15 6,0 7,1 8,2 9,3 10,4 9,4 10,5  11,6  12,7  13,8  14,9  15,10  0,11  1,12  2,13  3,14  4,155,0 6,1 7,2 8,3 7,3 8,4 9,5 10,6  11,7  12,8  13,9  14,10 15,11  0,12 1,13  2,14  3,15 4,0 5,1 6,2 5,2 6,3 7,4 8,5 9,6 10,7  11,8  12,9 13,10 14,11 15,12  0,13  1,14  2,15 3,0 4,1 3,1 4,2 5,3 6,4 7,5 8,6 9,710,8  11,9  12,10 13,11 14,12 15,13  0,14  1,15 2,0 1,0 2,1 3,2 4,3 5,46,5 7,6 8,7 9,8 10,9  11,10 12,11 13,12 14,13 15,14  0,15


7. The method of claim 1 wherein the method is for deinterleaving dataencoded using QPSK modulation.
 8. An apparatus comprising: adeinterleaver; the deinterleaver containing logic enabling: writing intoa buffer having 172,032 metrics arranged into an 84 by 8 array of 16 by16 blocks; wherein the buffer is partitioned into 4 subsets of rows; bywriting data into the buffer in groups of 8 metrics; wherein each of thegroups of 8 metrics are written in turn to each subset, in a column bycolumn ordering; and rearranging data in each 16 by 16 block of arraysaccording to a table; wherein the table specifies the rearrangedlocation of each metric in the 16 by 16 block.
 9. The apparatus of claim8 where the first elements of the 16 by 16 table entries form a Latinsquare.
 10. The apparatus of claim 8 wherein a data modulation formatfor the data is for a 16 QAM modulation.
 11. The apparatus of claim 10wherein symbol bits in each reliability class are balanced in eachconstituent codeword.
 12. The apparatus of claim 11 wherein the indicesof transmission of the metrics on the line, taken modulo N, where N istwice the number of metrics per symbol, are the same in each block. 13.The apparatus of claim 8 wherein the table is: 0,0 1,1 2,2 3,3 4,4 5,56,6 7,7 8,8 9,9 10,10 11,11 12,12 13,13 14,14 15,15 14,15 15,0  0,1 1,22,3 3,4 4,5 5,6 6,7 7,8 8,9  9,10 10,11 11,12 12,13 13,14 12,14 13,1514,0  15,1  0,2 1,3 2,4 3,5 4,6 5,7 6,8 7,9  8,10  9,11 10,12 11,1310,13 11,14 12,15 13,0  14,1  15,2  0,3 1,4 2,5 3,6 4,7 5,8 6,9  7,10 8,11  9,12  8,12  9,13 10,14 11,15 12,0  13,1  14,2  15,3  0,4 1,5 2,63,7 4,8 5,9  6,10  7,11  6,11  7,12  8,13  9,14 10,15 11,0  12,1  13,2 14,3  15,4  0,5 1,6 2,7 3,8 4,9  5,10  4,10  5,11  6,12  7,13  8,14 9,15 10,0  11,1  12,2  13,3  14,4  15,5  0,6 1,7 2,8 3,9 2,9  3,10 4,11  5,12  6,13  7,14  8,15 9,0 10,1  11,2  12,3  13,4  14,5  15,6 0,7 1,8 15,7  0,8 1,9  2,10  3,11  4,12  5,13  6,14  7,15 8,0 9,1 10,2 11,3  12,4  13,5  14,6  13,6  14,7  15,8  0,9  1,10  2,11  3,12  4,13 5,14  6,15 7,0 8,1 9,2 10,3  11,4  12,5  11,5  12,6  13,7  14,8  15,9  0,10  1,11  2,12  3,13  4,14  5,15 6,0 7,1 8,2 9,3 10,4  9,4 10,5 11,6  12,7  13,8  14,9  15,10  0,11  1,12  2,13  3,14  4,15 5,0 6,1 7,28,3 7,3 8,4 9,5 10,6  11,7  12,8  13,9  14,10 15,11  0,12  1,13  2,14 3,15 4,0 5,1 6,2 5,2 6,3 7,4 8,5 9,6 10,7  11,8  12,9  13,10 14,1115,12  0,13  1,14  2,15 3,0 4,1 3,1 4,2 5,3 6,4 7,5 8,6 9,7 10,8  11,9 12,10 13,11 14,12 15,13  0,14  1,15 2,0 1,0 2,1 3,2 4,3 5,4 6,5 7,6 8,79,8 10,9  11,10 12,11 13,12 14,13 15,14  0,15


14. The apparatus of claim 8 wherein a data modulation format for thedata is for a QPSK modulation.
 15. A system comprising: one or moredecoders; a deinterleaver; the deinterleaver containing logic enabling:writing data into a buffer having 172,032 metrics arranged into an 84 by8 array of 16 by 16 blocks; wherein the buffer is partitioned into 4subsets of rows according to a predetermined write sequence; applying amapping table to change data in each of the 16 by 16 block of arraysaccording to a table; wherein the table specifies a mapping of thelocation for each metric in the 16 by 16 block; and reading the data outof the buffer to serve as input for a first decoder and a seconddecoder.
 16. The system of claim 15 wherein the one or more decoder readdata from the buffer; wherein the one or more decoders switch betweenreading data from the buffer.
 17. The system of claim 15 where the firstelements of the 16 by 16 table entries form a Latin square.
 18. Theapparatus of claim 15 wherein a data modulation format for the data isfor a 16 QAM modulation.
 19. The apparatus of claim 15 wherein the tableis: 0,0 1,1 2,2 3,3 4,4 5,5 6,6 7,7 8,8 9,9 10,10 11,11 12,12 13,1314,14 15,15 14,15 15,0  0,1 1,2 2,3 3,4 4,5 5,6 6,7 7,8 8,9  9,10 10,1111,12 12,13 13,14 12,14 13,15 14,0  15,1  0,2 1,3 2,4 3,5 4,6 5,7 6,87,9  8,10  9,11 10,12 11,13 10,13 11,14 12,15 13,0  14,1  15,2  0,3 1,42,5 3,6 4,7 5,8 6,9  7,10  8,11  9,12  8,12  9,13 10,14 11,15 12,0 13,1  14,2  15,3  0,4 1,5 2,6 3,7 4,8 5,9  6,10  7,11  6,11  7,12  8,13 9,14 10,15 11,0  12,1  13,2  14,3  15,4  0,5 1,6 2,7 3,8 4,9  5,10 4,10  5,11  6,12  7,13  8,14  9,15 10,0  11,1  12,2  13,3  14,4  15,5 0,6 1,7 2,8 3,9 2,9  3,10  4,11  5,12  6,13  7,14  8,15 9,0 10,1  11,2 12,3  13,4  14,5  15,6  0,7 1,8 15,7  0,8 1,9  2,10  3,11  4,12  5,13 6,14  7,15 8,0 9,1 10,2  11,3  12,4  13,5  14,6  13,6  14,7  15,8  0,9 1,10  2,11  3,12  4,13  5,14  6,15 7,0 8,1 9,2 10,3  11,4  12,5  11,5 12,6  13,7  14,8  15,9   0,10  1,11  2,12  3,13  4,14  5,15 6,0 7,1 8,29,3 10,4  9,4 10,5  11,6  12,7  13,8  14,9  15,10  0,11  1,12  2,13 3,14  4,15 5,0 6,1 7,2 8,3 7,3 8,4 9,5 10,6  11,7  12,8  13,9  14,1015,11  0,12  1,13  2,14  3,15 4,0 5,1 6,2 5,2 6,3 7,4 8,5 9,6 10,7 11,8  12,9  13,10 14,11 15,12  0,13  1,14  2,15 3,0 4,1 3,1 4,2 5,3 6,47,5 8,6 9,7 10,8  11,9  12,10 13,11 14,12 15,13  0,14  1,15 2,0 1,0 2,13,2 4,3 5,4 6,5 7,6 8,7 9,8 10,9  11,10 12,11 13,12 14,13 15,14  0,15


20. The apparatus of claim 15 wherein a data modulation format for thedata is for a QPSK modulation.